Prospects for single shot diffraction imaging with laser-plasma driven high harmonic sources

  • Rachel Elizabeth Smith

Student thesis: Doctoral ThesisDoctor of Philosophy


Over 30 years since the first observations of high order harmonics generated from laser systems, high harmonic generation (HHG) remains one of the key routes to an intense, spatially coherent source of XUV radiation. The work presented in this thesis presents the numerical investigations conducted using the parallelized, second order relativistic particle-in-cell (PIC) code EPOCH [1], of high harmonics generated through intense interactions with a solid density plasma-target, with a particular focus on their application for single shot diffraction imaging techniques.

A novel combination of polarization gating techniques and a two-colour laser pulse is presented as a tool to isolate and enhance single attosecond scale pulses. Numerical results show that by using solid target HHG, a table top system is capable of generating very short wavelength radiation. Optimisation of laser parameters in both numerical simulations and experiments has great implications for the efficiency of high harmonic generation schemes. A systematic study ispresented, comparing such efficiencies in one and two dimensional simulations, as both the scale length of the plasma and the relative phase between the driving laser pulse and its frequency doubled component are varied. Using the two dimensional simulations, the study was extended to determine the effects of using a two-colour laser pulse on the energy distribution at the focal spot. Finally, numerical studies are used to determine the usability of table-top, two-colour, solid-target HHG systems for lensless imaging applications.

Date of AwardJul 2023
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsDepartment for Education
SupervisorBrendan Dromey (Supervisor) & Mark Yeung (Supervisor)


  • High harmonic generation
  • solid-plasma targets
  • laser-driven plasma
  • lensless Imaging
  • particle-in-cell simulations
  • plasma physics

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